The letter,which was shared on Twitter,reaffirmed Kate's dedication to the "vital role that children's hospices play in helping seriously ill children and families to have more precious moments." The Duchess has supported the children's hospicemovement since January 2012, when she became a Royal Patron of East Anglia’s Children’s Hospices. Kate shared the poignant statement in honor of Children's Hospice Week in the United Kingdom, which runs from May 21 through May 28.

The touching note also included a sweet detail about Kate's favorite and most cherished moments as a mother to Prince George, Princess Charlotte, and Prince Louis. "Spending quality time together is such an important aspect of family life and for me, as a mother, it is the simple family moments like playing outside together that I cherish," the Duchess wrote.

Royal fans have gotten a glimpse at Will, Kate, and their children playing outside through the years. Just weeks after welcoming Princess Charlotte, Kate was spotted playing on a lawn with Prince George while at a polo match in Tetbury, England.

IMAGE GETTY IMAGES

ADVERTISEMENT - CONTINUE READING BELOW

Duchess Kate and Prince George on June 14, 2015.

We've even seen the Cambridge family embracing the great outdoors in the winter, too. In 2016, the royals shared an adorable snowy family photo taken on a ski trip in the French Alps.